Dual ejection port firearm

ABSTRACT

Firearms with improved systems and methods of controlling which side of the firearm shell casings are ejected from, with ejection port covers on both sides of the firearm that open to provide cross ventilation, or both. In some embodiments, the bolt can be installed in one of two different orientations to select whether shell casings are ejected from the left or the right ejection port without a need to replace any parts. In a number of embodiments, spring loaded ejection port covers on both sides open when the firearm is fired or when the bolt or carrier of the firearm moves to provide cross ventilation through a passageway through the firearm to cool the firearm. The covers can be manually closed by the operator when the weapon is not being fired to keep dirt and debris out of the firearm.

RELATED PATENT APPLICATIONS

This patent application is a Continuation of U.S. patent applicationSer. No. 15/153,968 filed on May 13, 2016, titled DUAL EJECTION PORTFIREARM, which is a Continuation of U.S. patent application Ser. No.14/581,755 filed on Dec. 23, 2014, now issued as U.S. Pat. No.9,341,423, titled DUAL EJECTION PORT FIREARM, which claims priority toU.S. Provisional Patent Application No. 61/920,213, filed on Dec. 23,2013, titled FIREARM CAPABLE OF EJECTING SHELL CASINGS ON EITHER SIDE,and to U.S. Provisional Patent Application No. 61/920,234, also filed onDec. 23, 2013, titled, CROSS VENTILATION THROUGH EJECTION PORTS OFFIREARM which each have at least one inventor in common with the currentpatent application and the same assignee. The contents of these priorityprovisional patent applications are incorporated herein by reference.

FIELD OF THE INVENTION

Various embodiments of this invention relate to firearms. Particularembodiments relate to firearms having bilateral ejection ports or thatare capable of selectively ejecting shell casings on either side of thefirearm. Certain embodiments relate to firearms having active coolingsystems.

BACKGROUND OF THE INVENTION

Firearms have been used for several centuries for various purposesincluding as weapons for warfare, law enforcement, self defense,hunting, and target practice. Although many new weapons and weaponsystems have been developed, firearms are still widely used and soldiersare trained in firearm use and carry firearms in essentially all armiesthroughout the world. Over time, firearms have been improved in manyways, but opportunities for improvement still exist in particular areasand for particular aspects of these devices.

Firearms have been constructed with an ejection port where spent shellcasings exit the weapon. Firearms have been manufactured with ejectionports on either side of the weapon and different users prefer right sideor left side ejection ports, depending, for example, on whether the useris right handed or left handed or plans to shoot from a right handedstance or a left handed stance. Firearms have been sold that can beconverted from a right side ejection port to a left side ejection port,or vice versa, but such firearms typically required additional parts tomake the conversion. These additional parts either were not sold withthe firearm or added cost to the weapon. A need or potential for benefitor improvement exists for firearms that can be converted from a rightside ejection port to a left side ejection port, or vice versa, withoutadditional parts, more easily, more quickly, without adding complexityto the weapon, or a combination thereof, as examples.

In addition, firearms have been equipped with a dust cover over theejection port to keep dirt and debris from entering the ejection port.Moreover, firearms have been manufactured where the dust cover opensautomatically, for example, when the weapon is fired or when the bolt orcarrier is moved (e.g., in either direction). But such firearms havetypically opened the dust cover for only one ejection port at a time.Furthermore, it has long been recognized that firearms can overheat in abattlefield situation where the firearm is fired a large number of timesin a relatively short period of time. Firearms have been designed withvarious characteristics that promote cooling, including promotingventilation of the barrel. Needs or potential for benefit or improvementexist, however, for firearms that dissipate heat better, more easily,more quickly, from other parts of the firearm, without adding excessivecomplexity to the weapon, or a combination thereof, as examples.

Room for improvement exists over the prior art in these and other areasthat may be apparent to a person of skill in the art having studied thisdocument.

SUMMARY OF PARTICULAR EMBODIMENTS OF THE INVENTION

This invention provides, among other things, firearms with improvedsystems and methods of providing for ejection of shell casings fromeither side of the weapon. Various embodiments provide firearms with anejection port on each side of the weapon and different users canconfigure the weapon to use the right side or left side ejection port,depending, for example, on whether the user is right handed or lefthanded or plans to shoot from a right handed stance or a left handedstance. Particular embodiments do not require additional parts to makethe conversion (e.g., parts that either are not sold with the firearm oradd cost to the weapon). Certain embodiments provide firearms that canbe converted from a right side ejection port to a left side ejectionport, or vice versa, without additional parts, more easily, morequickly, without adding complexity to the weapon, or a combinationthereof, as examples.

This invention also provides firearms with improved systems and methodsof cooling of the weapon. Certain embodiments provide for both ejectionof shell casings and cooling of the weapon. Various embodiments providefirearms with an ejection port on each side of the weapon and differentembodiments provide enhanced cooling the weapon by opening both theright side and left side dust covers over the ejection ports, therebyproviding cross ventilation of the bolt and rear of the chamber.Further, various embodiments provide for covering of the cooling systemof a firearm, when not needed, to avoid the admission of dirt or debris.

Other embodiments, besides firearms, include bolts for firearms andmethods of configuring or obtaining or providing a firearm or bolt for afirearm, for example, to selectably eject shell casings through eitherside of the firearm, for instance, with features described herein.Further embodiments include bolts for firearms, carriers for firearms,and methods of configuring, obtaining, or providing a firearm thatprovide cross ventilation through the firearm, for instance, throughbilateral ejection ports.

Various embodiments provide, for example, as an object or benefit, thatthey partially or fully address or satisfy one or more of the needs,potential areas for benefit, or opportunities for improvement describedherein, or known in the art, as examples. In a number of embodiments,improvements to firearms herein provide for firearms that are morereliable, that last longer, that are more adaptable, that can be used inconditions that are more extreme, that handle abuse well, that workbetter, that are easier to use, that are easier to maintain, that areless expensive to manufacture, that have a lower lifecycle cost, thatoffer more options for use, that can be fired at a high firing rate fora longer period of time, or a combination thereof. In addition, variousother embodiments of the invention are also described herein, and otherbenefits of certain embodiments may be apparent to a person of skill inthis area of technology.

Specific embodiments include various firearms that include, forinstance, a left ejection port, a right ejection port, a bolt having afirst side and a second side, or a combination thereof. In variousembodiments, for example, the bolt can be installed in the firearm withthe first side up, the bolt can be installed in the firearm with thesecond side up, when the bolt is installed in the firearm with the firstside up, shell casings are ejected though the right ejection port, andwhen the bolt is installed in the firearm with the second side up, shellcasings are ejected though the left ejection port. In some embodiments,for example, the firearm includes a left side and a right side, the leftejection port is on the left side of the firearm, and the right ejectionport is on the right side of the firearm. Further, in a number ofembodiments, the bolt has a central axis, and when the bolt is installedin the firearm with the second side up, the bolt is rotated 180 degreesaround the central axis from when the bolt is installed in the firearmwith the first side up.

Further, in some embodiments, for example, the bolt includes an ejectionpin, and when the bolt is installed in the firearm with the first sideup so that shell casings are ejected though the right ejection port, theejection pin is left of the central axis of the bolt, between thecentral axis and the left side of the firearm. Further still, in anumber of embodiments, when the bolt is installed in the firearm withthe second side up so that shell casings are ejected though the leftejection port, the ejection pin is right of the central axis of thebolt, between the central axis and the right side of the firearm.

Even further, in some embodiments, for example, the bolt includes anextractor claw, and when the bolt is installed in the firearm with thefirst side up so that shell casings are ejected though the rightejection port, the extractor claw is right of the central axis of thebolt, between the central axis and the right side of the firearm. Evenfurther still, in a number of embodiments, when the bolt is installed inthe firearm with the second side up so that shell casings are ejectedthough the left ejection port, the extractor claw is left of the centralaxis of the bolt, between the central axis and the left side of thefirearm.

Moreover, in some embodiments, for example, the bolt includes a firstset of ejection features on the first side of the bolt and a second setof ejection features on the second side of the bolt, and the second setof ejection features is a mirror opposite of the first set of ejectionfeatures. Further, in some embodiments, for example, the firearmincludes a receiver that includes the left ejection port and the rightejection port, the bolt is contained within the receiver, and the boltand the receiver are configured so that the bolt can be installed in thereceiver with the first side up and the bolt can be installed in thereceiver with the second side up. Further still, in some embodiments,for example, the firearm includes a carrier that includes a forward end,the bolt engages the carrier at the forward end of the carrier, and thebolt and the forward end of the carrier are configured so that the boltcan operationally engage the forward end of the carrier with the firstside up and the bolt can operationally engage the forward end of thecarrier with the second side up.

Other specific embodiments include various firearms that include a leftside, a right side, a left port at the left side, a right port at theright side, a left cover at the left port, a right cover at the rightport, and a passageway extending from the left port to the right port.Further a number of embodiments include an opening mechanism thatautomatically opens both the left cover and the right cover when thefirearm is discharged. In various embodiments, for example, when theleft cover is closed, the left cover covers the left port covering thepassageway at the left side, and when the right cover is closed, theright cover covers the right port covering the passageway at the rightside. Still further, in a number of such embodiments, when the leftcover opens, the left cover uncovers the left port opening thepassageway at the left side, and when the right cover is opened, theright cover uncovers the right port opening the passageway at the rightside.

In some embodiments, for example, the opening mechanism automaticallyopens both the left cover and the right cover when the firearm isdischarged. Further, in some embodiments, for instance, the openingmechanism automatically opens both the left cover and the right coverwhen a round is chambered within the firearm. Still further, in someembodiments, for example, the left cover is a left ejection port, theright cover is a right ejection port, the left cover is a left dustcover at the left ejection port, and the right cover is a right dustcover at the right ejection port. Even further, in some embodiments, forexample, the firearm includes a receiver, a left hinge, a right hinge, aleft spring, a right spring, a left latch, and a right latch. In anumber of embodiments, for instance, the left dust cover is attached tothe receiver with the left hinge, the right dust cover is attached tothe receiver with the right hinge, the left dust cover is biased openwith the left spring, the right dust cover is biased open with the rightspring, the left dust cover is held closed with the left latch, and theright dust cover is held closed with the right latch.

Moreover, in some embodiments, for example, the left dust cover is heldclosed with the left latch when the left dust cover is manually pushedclosed, the right dust cover is held closed with the right latch whenthe right dust cover is manually pushed closed, and the openingmechanism opens the left dust cover and the right dust cover byreleasing the left latch and the right latch. Further still, in someembodiments, for example, the firearm includes a bolt, the openingmechanism includes a left bolt feature and a right bolt feature, theopening mechanism includes a left cover feature and a right coverfeature, or both. Even further still, in a number of embodiments, theleft cover feature is part of the left dust cover, the right coverfeature is part of the right dust cover, the left dust cover opens whenthe left bolt feature contacts the left cover feature, and the rightdust cover opens when the right bolt feature contacts the right coverfeature, or a combination thereof, as examples.

Still other specific embodiments include various firearms that include aleft ejection port, a right ejection port, a left dust cover at the leftejection port, a right dust cover at the right ejection port, apassageway extending from the left ejection port to the right ejectionport, and a bolt carrier group having a first feature and a secondfeature. In various embodiments, for example, the first featureautomatically opens the left dust cover when the bolt carrier groupmoves and the second feature automatically opens the right dust coverwhen the bolt carrier group moves, for instance, to provide crossventilation through the passageway to the bolt carrier group when theleft dust cover and the right dust cover are open. Further, in certainembodiments, for example, the bolt carrier group includes a carrier anda bolt having a first side and a second side, the bolt can be installedin the carrier with the first side up, and the bolt can be installed inthe carrier with the second side up. Moreover, in a number ofembodiments, when the bolt is installed in the carrier with the firstside up, shell casings are ejected though the right ejection port, andwhen the bolt is installed in the carrier with the second side up, shellcasings are ejected though the left ejection port.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings provided herewith illustrate, among other things, examplesof certain aspects of particular embodiments. Other embodiments maydiffer. Various embodiments may include aspects shown in the drawings,described in the specification (including the claims), known in the art,or a combination thereof, as examples. Other embodiments, however, maydiffer.

FIG. 1 is a right side view of an embodiment of a firearm that includesa dust cover on the right side that is open;

FIG. 2 is a top view of the firearm of FIG. 1 showing dust covers openon both sides of the firearm;

FIG. 3 is a top cross-sectional view of the firearm of FIGS. 1 and 2,taken along section A-A in FIG. 1, illustrating, among other things, thebolt of the firearm;

FIG. 4 is a top detail view of part of the firearm of FIG. 3illustrating the ejection pin and extractor claw of the bolt in a firstorientation;

FIG. 5 is the same top detail view of FIG. 4 of the part of the firearmof FIG. 3 except illustrating the ejection pin and extractor claw of thebolt in a second orientation with the bolt rotated 180 degrees from thefirst orientation;

FIG. 6 is a right side detail view of part of the firearm of FIG. 1illustrating, among other things, the right ejection port and dustcover;

FIG. 7 is an isometric view of the bolt carrier group of the firearm ofFIGS. 1-6 illustrated in the first orientation of FIG. 4;

FIG. 8 is an isometric view of the bolt carrier group of the firearm ofFIGS. 1-6 illustrated in the second orientation of FIG. 5;

FIG. 9 is a top view of the bolt of the firearm of FIGS. 1-6 illustratedin the first orientation of FIGS. 4 and 7;

FIG. 10 is a right side view of the bolt of the firearm of FIGS. 1-6illustrated in the first orientation of FIGS. 4 and 7; and

FIG. 11 is a left side view of the bolt of the firearm of FIGS. 1-6illustrated in the second orientation of FIGS. 5 and 8.

DETAILED DESCRIPTION OF EXAMPLES OF EMBODIMENTS

This patent application describes, among other things, examples ofcertain embodiments, and certain aspects thereof. Other embodiments maydiffer from the particular examples described in detail herein. Variousembodiments are or concern firearms, for example, having improvementsover the prior art. Different embodiments include firearms, mechanismsfor firearms, bolts for firearms, methods concerning ejection of shellcasings from firearms, and methods concerning cooling of and/or ejectionof shell casings from firearms, as examples.

Certain embodiments include firearms with improved systems and methodsof controlling which side of the firearm shell casings are ejected from,firearms with ejection port covers on both sides of the firearm thatopen to provide cross ventilation, and firearms with both such features.In some embodiments, the bolt can be installed in one of two differentorientations to select whether shell casings are ejected from the leftor the right ejection port, for example, in a number of embodiments,without a need to replace any parts. In various embodiments, springloaded ejection port covers on both sides open when the firearm is firedor when the bolt or carrier of the firearm moves, as examples, toprovide cross ventilation through a passageway through the firearm, forinstance, to cool the firearm. The covers can be manually closed by theoperator, in a number of embodiments, when the weapon is not beingfired, to keep dirt and debris out of the firearm.

In a number of embodiments, for example, a firearm (e.g., 10 shown inFIGS. 1-3) includes, among other things, a left ejection port (e.g., 41shown in FIGS. 4 and 5), a right ejection port (e.g., 42 shown in FIGS.1 and 4-6); and a bolt (e.g., 70 shown in FIGS. 3-5 and 7-11). Invarious embodiments, the bolt (e.g., 70) has a first side (e.g., 71shown in FIGS. 7 and 9-11) and a second side (e.g., 82 shown in FIGS. 8,10, and 11). In various embodiments, as used herein, a “bolt” is a boltassembly. In some embodiments, the firearm (e.g., 10) is configured toselectably eject shell casings through either side of the firearm.Further, in a number of embodiments, for instance, the firearm isconfigured so that a bolt (e.g., 70) of the firearm can be installed inthe firearm in either of two different orientations (e.g., shown inFIGS. 7 and 8).

In certain embodiments, when the bolt (e.g., 70) is installed, forexample, in a first orientation (e.g., as shown in FIG. 7), shellcasings are ejected (i.e., when the firearm is fired or discharged)though a right ejection port (e.g., 42), and when the bolt is installedin a second orientation (e.g., as shown in FIG. 8), shell casings areejected (i.e., when the firearm is fired or discharged) though a leftejection port (e.g., 41). For example, in various embodiments, the bolt(e.g., 70) can be installed in the firearm with the first side (e.g.,71) up and the bolt can also (i.e., alternatively, at the option of theoperator or other person who assembles or maintains the firearm) beinstalled in the firearm with the second side (e.g., 82) up. As usedherein, where a bolt “can be installed” in a firearm “with the firstside up” and “with the second side up” the bolt can be removed andreinstalled by an operator of the firearm, in either orientation (i.e.,ether first side or second side up) without destruction or replacementof any parts of the firearm and in the course of ordinary maintenance ofthe firearm that would typically be performed by the owner or operatorof the weapon, for instance, for cleaning and/or lubrication of theweapon.

In this context, “up”, as well as “left” and “right” are relative to theorientation of the firearm (i.e., when the firearm is in its normalorientation when being used with the barrel (e.g., 13) horizontal asshown in FIG. 1). In this context “can be installed” means withoutchanging out or modifying any parts of the firearm and in a manner thatrenders the firearm operational for use firing multiple rounds. Furtherin certain embodiments, when the bolt (e.g., 70) is installed in thefirearm with the first side (e.g., 71) up, shell casings are ejectedthough the right ejection port (e.g., 42), and when the bolt isinstalled in the firearm with the second side (e.g., 82) up, shellcasings are ejected though the left ejection port (e.g., 41). In thiscontext, the shell casings are ejected through the appropriate ejectionport when the firearm is discharged.

In a number of embodiments, each ejection port (e.g., 41 and 42) has adust cover (e.g., 21 and 22 shown in FIGS. 1-6), for example, that canbe closed by the operator but that opens automatically, for example,when the bolt moves (e.g., in a number of embodiments, in eitherdirection). In this context, as used herein, “can be closed by theoperator” means that a typical person who fires the firearm canphysically close the cover with the operator's fingers without any toolsor other materials and without significant harm or discomfort to theoperator so that the cover stays closed, for example, until the bolt ismoved. In some embodiments, the dust cover for the ejection port that isnot being used for the ejection of shell casings remains closedregardless of the movement of the bolt. In other embodiments, however,the dust cover for the ejection port that is not being used for theejection of shell also opens when the bolt moves, for example, toprovide cross ventilation for cooling of the weapon, for instance, inthe event a large number of shots are fired in a relatively short periodof time.

In various embodiments, the bolt (e.g., 70) includes an ejection pin(e.g., 85 shown in FIGS. 4, 5, 7 and 8), the bolt includes a extractorclaw (e.g., 86 shown in FIGS. 4, 5, 7 and 8), or both. In differentembodiments, the extractor claw (e.g., 86) or extraction claw grabs thecasing and the ejection pin (e.g., 85) pushes the casing toward thedirection of the extractor claw. Further, in a number of embodiments,the firearm includes a left side (e.g., 31 shown in FIGS. 2-5) and aright side (e.g., 32 shown in FIGS. 1-6), the left ejection port (e.g.,41) is on the left side of the firearm, the right ejection port (e.g.,42) is on the right side of the firearm (e.g., 10), and the bolt (e.g.,70) has a central axis (e.g., 99 shown in FIGS. 9-11). The central axis(e.g., 99) can be parallel to or concentric with the barrel (e.g., 13,for instance, the bore of the barrel) of the firearm (e.g., 10), in someembodiments, for example. Even further, in some embodiments, when thebolt (e.g., 70) is installed in the firearm (e.g., 10) with the secondside (e.g., 82) up, the bolt is rotated 180 degrees (e.g., relative tothe remainder of the firearm or the receiver, for instance) around thecentral axis (e.g., 99) from (i.e., in comparison to) when the bolt(e.g., 70) is installed in the firearm with the first side (e.g., 71)up.

In a number of embodiments where the bolt (e.g., 70) includes anejection pin (e.g., 85), when the bolt is installed in the firearm(e.g., 10) with the first side up (e.g., 71) so that shell casings areejected though the right ejection port (e.g., 42), the ejection pin(e.g., 85) is left of the central axis (e.g., 99) of the bolt (e.g.,70), for instance, between the central axis and the left side (e.g., 31)of the firearm (e.g., 10). Further, in a number of embodiments, when thebolt (e.g., 70) is installed in the firearm (e.g., 10) with the secondside (e.g., 82) up so that shell casings are ejected though the leftejection port (e.g., 41), the ejection pin (e.g., 85) is right of thecentral axis (e.g., 99) of the bolt (e.g., 70), for example, between thecentral axis (e.g., 99) and the right side (e.g., 32) of the firearm(e.g., 10).

In various embodiments, installing the bolt (e.g., 70) with theextractor claw (e.g., 86) on the left side (e.g., left of centerline 99)will eject the shells on the left side (e.g., 31) of the firearm (e.g.,10). Further, in a number of embodiments, installing the bolt (e.g., 70)with the ejection pin (e.g., 85) on the right side (e.g., right ofcenterline 99) will eject the shells on the left side (e.g., 31) of thefirearm (e.g., 10). On the other hand, in a number of embodiments,installing the bolt (e.g., 70) with the extractor claw (e.g., 86) on theright side (e.g., right of centerline 99) will eject the shells on theright side (e.g., 32) of the firearm (e.g., 10). Further, in a number ofembodiments, installing the bolt (e.g., 70) with the ejection pin (e.g.,85) on the left side (e.g., left of centerline 99) will eject the shellson the right side (e.g., 32) of the firearm (e.g., 10).

Further, in a number of embodiments where the bolt (e.g., 70) includes aextractor claw (e.g., 86), when the bolt is installed in the firearm(e.g., 10) with the first side (e.g., 71) up so that shell casings areejected though the left ejection port (e.g., 41), the extractor claw(e.g., 86) is left of the central axis (e.g., 99) of the bolt (e.g.,70), between the central axis and the left side (e.g., 31) of thefirearm (e.g., 10). Further, in a number of embodiments, when the bolt(e.g., 70) is installed in the firearm with the second side (e.g., 82)up so that shell casings are ejected though the right ejection port(e.g., 42), the extractor claw (e.g., 86) is right of the central axis(e.g., 99) of the bolt, between the central axis and the right side(e.g., 32) of the firearm.

In some embodiments, the bolt (e.g., 70) includes a first set ofejection features on the first side (e.g., 71) of the bolt and a secondset of ejection features on the second side (e.g., 82) of the bolt, andthe second set of ejection features is a mirror opposite (e.g.,identical but opposite hand) of the first set of ejection features(i.e., within an appropriate tolerance). In a number of embodiments,these ejection features direct the shell casing to the appropriateejection port (e.g., 41 or 42), for example, immediately after thefirearm is discharged. In certain embodiments, the second set ofejection features is a mirror opposite of the first set of ejectionfeatures across a plane through the bolt (e.g., 70) that includes thecentral axis (e.g., 99) of the bolt, for example. Further, in someembodiments, the bolt can contain other features that are identical ormirror opposites on the first and second sides of the bolt, besides theejection features, and in certain embodiments, the bolt can containfurther features that are different on the first and second sides of thebolt.

In the embodiment illustrated, FIG. 7 illustrates a first set ofejection features on first side 71 of the bolt and FIG. 8 illustrates asecond set of ejection features on second side 82 of the bolt. In thisembodiment, the first and second sets of ejection features includefeatures that are mirror opposite (e.g., identical but opposite hand) inthese two views. In addition, FIGS. 10 and 11 illustrate first side 71and second side 82 from right side and left side views, depicting, amongother things, the ejection features on first side 71 and second side 82,in the embodiment shown. These features include a first cartridgestripping face 100 at the forward-facing surface of the bolt associatedwith first side 71 and a second cartridge stripping face 102 associatedwith second side 82. These faces 100, 102 strip the cartridges from amagazine, and are both mirror images of each other about a horizontalplane defined at the central axis of the bolt, and are also rotationallysymmetrical 180 degrees apart about a central axis defined by the bolt.

In a number of embodiments, the left ejection port (e.g., 41) and theright ejection port (e.g., 42) are in the receiver (e.g., 11) of thefirearm (e.g., 10). In various embodiments, the bolt (e.g., 70) iscontained within the receiver (e.g., 11) and the bolt and the receiverare configured so that the bolt can be installed in the receiver withthe first side (e.g., 71) up and the bolt can be installed in thereceiver with the second side (e.g., 82) up. As used herein, a firstpart or set of parts being “configured” for a first function requiresthat the first part or set of parts be specifically adapted to performthe first function. In other embodiments, however, the first part or setof parts can be capable of the first function, which does not requiresuch a specific adaptation. For example, in other embodiments, the boltis capable of being installed in the receiver with the first side up andthe bolt is capable of being installed in the receiver with the secondside up. Further, in some embodiments, for example, the receiver iscapable of receiving the bolt with the first side up and the receiver iscapable of receiving the bolt in the receiver with the second side up.

Further, as used herein, a bolt being contained within a receiver meansthat the bolt (e.g., 70) is located within the receiver (e.g., 11) whenthe firearm (e.g., 10) is assembled and ready to fire. In a number ofembodiments, such bolt can be shipped or sold external to the receiver.In a number of embodiments, the receiver (e.g., 11) consists of orincludes an upper receiver and a lower receiver that can be separated,for example, to access the bolt, bolt carrier group, other internalcomponents, or a combination thereof. In some embodiments, for instance,the upper receiver and the lower receiver are hingedly attached to eachother, for instance, at a forward end.

In some embodiments, this receiver (e.g., 11) is specifically the upperreceiver of the firearm (e.g., 10). Further, in a number of embodiments,the firearm includes a carrier (e.g., 75) having a forward end (e.g.,76) and a rearward or aft end (e.g., 77) opposite the forward end. Invarious embodiments, the bolt (e.g., 70) engages the carrier (e.g., 75)at the forward end (e.g., 76) of the carrier. In various embodiments,the bolt (e.g., 70) and the forward end (e.g., 76) of the carrier (e.g.,75) are configured so that the bolt can operationally engage the forwardend of the carrier with the first side (e.g., 71) up and the bolt canoperationally engage the forward end of the carrier with the second side(e.g., 82) up (i.e., without rotating the carrier). As used herein,“operationally engage” means engage in a manner so that the firearm(e.g., 10) can fire multiple rounds and operate properly.

Broadly speaking, in a number of embodiments, a firearm (e.g., 10)includes a left side (e.g., 31), a right side (e.g., 32), a left cover(e.g., 21) at the left side, a right cover (e.g., 22) at the right side,a passageway (e.g., 66) extending from the left side (e.g., 31) to theright side (e.g., 32), and an opening mechanism (e.g., bolt protrusions91 and 92 on bolt 70 shown in FIGS. 9-11) that opens both the left cover(e.g., 21) and the right cover (e.g., 22). Such a cover can be anejection port cover, for example, in some embodiments, as shown. Otherembodiments may have a different type of cover. In a number ofembodiments, such a passageway (e.g., 66) can provide for crossventilation, for example, between the two covers.

Moreover, such an opening mechanism (e.g., bolt protrusions 91 and 92 onbolt 70) can be an apparatus (e.g., bolt protrusions 91 and 92 on bolt70) that opens the covers. In a number of embodiments, an openingmechanism (e.g., bolt protrusions 91 and 92 on bolt 70), or parts thatform or contribute to the opening mechanism, can have other functions aswell. In some embodiments, for instance, an opening mechanism caninclude a bolt (e.g., 70) for the firearm (e.g., 10 or part or multipleparts of the bolt, for instance, bolt protrusions 91 and 92 on bolt 70).Further, in some embodiments, an opening mechanism (e.g., boltprotrusions 91 and 92 on bolt 70) can include a carrier (e.g., 75) forthe firearm or part or multiple parts of the carrier, as other examples.

Further, in various embodiments, a firearm (e.g., 10) includes a leftport (e.g., 41) at the left side (e.g., 31), a right port (e.g., 42) atthe right side (e.g., 32), a left cover (e.g., 21) at the left port, aright cover (e.g., 22) at the right port, a passageway (e.g., 66, forinstance, through the firearm) extending from the left port (e.g., 41)to the right port (e.g., 42), and an opening mechanism (e.g., boltprotrusions 91 and 92 on bolt 70) that automatically opens both the leftcover and the right cover when the firearm is discharged. In a number ofembodiments, when the left cover (e.g., 21) is closed, the left covercovers the left port (e.g., 41) covering the passageway (e.g., 66) atthe left side (e.g., 31), and when the right cover (e.g., 22) is closed,the right cover covers the right port (e.g., 42) covering the passageway(e.g., 66) at the right side (e.g., 32). Moreover, in a number ofembodiments, such a covering (e.g., 21 or 22) is not necessarily air orwater tight, but can serve to reduce or eliminate the amount of dust,dirt, rain, snow, mud, debris, or other material that enters the port orports (e.g., when the firearm is not being fired). Even further, invarious embodiments, when the left cover (e.g., 21) opens, the leftcover uncovers the left port (e.g., 41) opening the passageway (e.g.,66) at the left side (e.g., 31), and when the right cover (e.g., 22) isopened, the right cover uncovers the right port (e.g., 42) opening thepassageway (e.g., 66) at the right side (e.g., 32), for example.

In a number of embodiments, the opening mechanism (e.g., boltprotrusions 91 and 92 on bolt 70) automatically opens both the leftcover (e.g., 21) and the right cover (e.g., 22) when the firearm (e.g.,10) is discharged. Further, in some embodiments, the opening mechanism(e.g., bolt protrusions 91 and 92 on bolt 70) automatically opens boththe left cover and the right cover when a round is chambered within thefirearm. Still further, in some embodiments, the opening mechanismautomatically opens both the left cover and the right cover when thebolt moves (e.g., either forward or rearward) within the firearm. Evenfurther, in some embodiments, the firearm includes a carrier (e.g., 75)and the opening mechanism automatically opens both the left cover andthe right cover when the carrier moves (e.g., forward or rearward)within the firearm, as another example.

As used herein, “automatically”, in the context of opening a cover,means without the human operator of the firearm manually taking somespecific action to open the cover (i.e., other than firing the firearmor pulling back the bolt, for instance, with the charging handle), suchas manually pulling the cover open, manually actuating a latch thatholds the cover closed, or manually operating any control that initiatesthe action of opening one or more covers without also performing somehigher function. Further, as used herein, unless stated otherwise, theopening of a cover is considered to be “automatically” performed if theopening of the cover is triggered by the firing of the firearm, movingof the bolt or carrier (e.g., by firing the firearm or moving with thecharging handle to cock the firearm), firing or moving of one or morerounds within the firearm, or the releasing of a safety for the firearm.

In particular embodiments, the left port and the right port are ejectionports and the left cover and the right cover are ejection port covers.Further, in certain embodiments, the left and right covers are dustcovers. Other embodiments, however, may differ. In particularembodiments, a firearm (e.g., 10) includes a left ejection port (e.g.,41), a right ejection port (e.g., 42), a left dust cover (e.g., 21) atthe left ejection port, a right dust cover (e.g., 22) at the rightejection port, a passageway (e.g., 66) extending from the left ejectionport to the right ejection port, and an opening mechanism (e.g., boltprotrusions 91 and 92 on bolt 70) that automatically opens both the leftdust cover and the right dust cover when the firearm is discharged, whena round is chambered within the firearm, when the bolt moves within thefirearm, when the carrier moves within the firearm, or a combinationthereof. As used herein, a dust cover (e.g., 21 or 22) is capable ofkeeping out at least some dust from the passageway (e.g., 66) when thedust cover is closed in comparison with when the dust cover is open. Asused herein, however, a dust cover does not necessarily keep out everyparticle of dust. Further, as used herein, an ejection port (e.g., 41 or42) is a port where shell casings are ejected from the firearm oncefired, at least if the firearm is configured to use that port to ejectshell casings. In a number of embodiments, only one ejection port isused at a time for ejecting shell casings, but both ports that can beused for ejecting shell casings (e.g., depending on how the firearm isassembled) are considered to be ejection ports (e.g., left and rightejection ports).

In various embodiments, the firearm (e.g., 10) includes a left hinge(e.g., 51 shown in FIGS. 4 and 5), a right hinge (e.g., 52 shown inFIGS. 4 and 5), or both. In certain embodiments, for example, the leftcover (e.g., 21) or dust cover is attached to the receiver (e.g., 11)with the left hinge (e.g., 51), and the right cover (e.g., 22) or dustcover is attached to the receiver with the right hinge (e.g., 52). In anumber of embodiments, the covers pivot at the hinge, for example, toopen or close. In some embodiments, the hinge is at the top of thecover, the top of the port, or both, for example. In other embodiments,however, the hinge (e.g., 51 and 52) is at the bottom of the cover(e.g., 21 and 22), the bottom of the port (e.g., 41 or 42), or both, forexample (e.g., as shown). In some embodiments, the cover pivots orswings (e.g., at the hinge) out and up to open, or out and down (e.g.,as shown) to open, for example, 90 degrees, more than 90 degrees, orbetween 90 and 180 degrees, as examples.

Further, in some embodiments, the firearm (e.g., 10) includes a leftspring (e.g., 56 shown in FIGS. 2, 4, and 5) and a right spring (e.g.,57 shown in FIGS. 1, 2, and 4-6). Even further, in particularembodiments, the left cover or dust cover (e.g., 21) is biased (e.g.,pushed or pulled) open with the left spring (e.g., 56), and the rightcover or dust cover (e.g., 22) is biased open with the right spring(e.g., 57) for instance, about or at the left and right hinges (e.g., 51and 52), respectively. Further still, in a number of embodiments,including the embodiment shown, the left spring (e.g., 56) is a helicalspring and the right spring (e.g., 57) is a helical spring, and incertain embodiments, the left spring (e.g., 56) is a torsion spring andthe right spring (e.g., 57) is a torsion spring, as examples. In someembodiments (e.g., as shown), helical springs are also torsion springs,but other embodiments may differ in one or both of these respects. In anumber of embodiments, the springs bias or hold the covers open unlessthe covers are manually pushed or held closed.

Moreover, in some embodiments, the firearm (e.g., 10) includes a leftlatch (e.g., 46 shown in FIGS. 4 and 5) and a right latch (e.g., 47shown in FIGS. 4-6), the left cover or dust cover (e.g., 21) is heldclosed with the left latch (e.g., 46), and the right cover or dust cover(e.g., 22) is held closed with the right latch (e.g., 57). In a numberof embodiments, the covers (e.g., 21 and 22) are held closed by theselatches (e.g., 46 and 47) against the opening forces applied by thesprings (e.g., 56 and 57). In some embodiments, a latch (e.g., 46 or 47)may include an interference fit, a detent, a magnet, another spring, ora combination thereof, as examples. In certain embodiments, a detentengages a small undercut on the inside of the port opening on the upperreceiver, for example. This allows the cover to remain securely closeduntil the bolt and/or carrier move back or forward, for instance, toautomatically open the cover. In this example, the latch includes thedetent and the undercut. In some embodiments, the latch further includesa spring (e.g., that pushes the detent).

In a number of embodiments, the left cover or dust cover (e.g., 21) isheld closed with the left latch (e.g., 46) when the left cover or dustcover is manually pushed closed (e.g., against the force of the leftspring, for instance, 56), and the right cover or dust cover (e.g., 22)is held closed with the right latch (e.g., 47) when the right cover ordust cover is manually pushed closed. The person or operator using thefirearm (e.g., 10) may manually close one or both dust covers (e.g., 21,22, or both) by pushing it or them closed (e.g., with a hand or fingers,bare or gloved), for example, when the person or operator is finishedfiring the firearm (e.g., 10), when the firearm is sufficiently cool, orwhen the person or operator perceives a need to keep foreign materialsout of the firearm (e.g., out of ports 41, 42, or both), as examples. Insome embodiments, the opening mechanism opens (e.g., automatically) theleft cover or dust cover and the right cover or dust cover by releasingthe left latch and the right latch. Further, in certain embodiments, theopening mechanism opens (e.g., automatically) the left cover or dustcover and the right cover or dust cover by pushing the left cover andthe right cover open, overcoming the left latch and the right latch.

Further, in various embodiments, the opening mechanism includes a leftbolt feature and a right bolt feature (i.e., located on the bolt of thefirearm). In particular embodiments, the left bolt feature includes aleft bolt protrusion and the right bolt feature includes a right boltprotrusion, as examples. Bolt protrusions 91 and 92 on bolt 70 areexamples of left and right bolt features and left and right boltprotrusions, as examples. Further still, in some embodiments, thefirearm includes a carrier, and the opening mechanism includes a leftcarrier feature and a right carrier feature. In particular embodiments,the left carrier feature includes a left carrier protrusion and theright carrier feature includes a right carrier protrusion, as otherexamples. In other embodiments, such a bolt or carrier feature can be ahole, a pin, a tab, or an indentation, as other examples.

Moreover, in various embodiments, the bolt (e.g., 70) includes anejection pin (e.g., 85), the bolt includes a extractor claw (e.g., 86),or both. Still further, in some embodiments, the opening mechanismincludes a left cover feature (e.g., 26 shown in FIGS. 2, 4, and 5) anda right cover feature (e.g., 27 shown in FIGS. 1, 2, and 4-6). Incertain embodiments, the left cover feature (e.g., 26) is part of theleft cover or dust cover (e.g., 21) and the right cover feature (e.g.,27) is part of the right cover or dust cover (e.g., 22), as examples(e.g., as shown). Even further, in particular embodiments, the leftcover feature (e.g., 26) is or includes a left cover protrusion and theright cover feature (e.g., 27) is or includes a right cover protrusion.In other embodiments, such a cover feature can be a hole, a pin, a tab,or an indentation, as other examples.

Even further still, in some embodiments, the left cover or dust cover(e.g., 21) opens when the left bolt feature (e.g., 91) or carrierfeature (e.g., in other embodiments) contacts or strikes the left coverfeature (e.g., 26) and the right cover or dust cover (e.g., 22) openswhen the right bolt feature (e.g., 92) or carrier feature (e.g., inother embodiments) contacts or strikes the right cover feature (e.g.,27), as examples. Such contact can initiate opening of the covers (e.g.,21 and 22), for example, by pushing the covers outward to overcome thelatches (e.g., 26 and 27) and allow the springs (e.g., 56 and 57) toopen the covers for the ejection of shell casings, cross ventilation andcooling of the firearm (e.g., 10), or both. In other embodiments, thebolt, carrier, or opening mechanism contacts the latch to open thecovers, as other examples.

Certain embodiments include various firearms (e.g., 10) that include aleft ejection port (e.g., 41), a right ejection port (e.g., 42), a leftdust cover (e.g., 21) at the left ejection port, a right dust cover(e.g., 22) at the right ejection port, a passageway (e.g., 66) extendingfrom the left ejection port to the right ejection port, and a boltcarrier group (e.g., bolt 70 and carrier 75) having a first feature(e.g., bolt protrusion 91) and a second feature (e.g., bolt protrusion92). In various embodiments, for example, the first feature (e.g., boltprotrusion 91) automatically opens the left dust cover (e.g., 21) at theleft ejection port 41) when the bolt carrier group (e.g., bolt 70 andcarrier 75) moves and the second feature (e.g., bolt protrusion 92)automatically opens the right dust cover (e.g., 22) at the rightejection port (e.g., 42) when the bolt carrier group moves, for example,to provide cross ventilation through the passageway (e.g., 66) to thebolt carrier group when the left dust cover and the right dust cover areopen. In a number of embodiments, opening of the dust covers (e.g., 21and 22) also allows shell casings to be ejected through (e.g., one of)the ejection ports (e.g., 41 and 42), for instance, depending on theorientation in which the bolt (e.g., 70) is installed.

Further, in various embodiments, for example, the bolt carrier groupincludes a carrier (e.g., 75) and a bolt (e.g., 70) having a first side(e.g., 71) and a second side (e.g., 82). In a number of embodiments, forexample, the bolt (e.g., 70) can be installed in the carrier (e.g., 75)with the first side up (e.g., 71 as shown in FIG. 7), and the bolt(e.g., 70) can be installed in the carrier (e.g., 75) with the secondside up (e.g., 82 as shown in FIG. 8), i.e., relative to the orientationof the carrier (e.g., 75). Moreover, in a number of embodiments, whenthe bolt (e.g., 70) is installed in the carrier (e.g., 75) with thefirst side (e.g., 71) up, shell casings are ejected though the rightejection port (e.g., 42), and when the bolt (e.g., 70) is installed inthe carrier (e.g., 75) with the second side (e.g., 82) up, shell casingsare ejected though the left ejection port (e.g., 41).

In a number of embodiments, the firearm is a rifle. In particularembodiments, for example, the firearm is an assault rifle, such as anAR-15 or an M-16. In some embodiments, the firearm can be asemi-automatic firearm or a fully automatic firearm, as examples.Further, in particular embodiments, the firearm is a rifle configured toselectably (e.g., via operation of a selector lever) fire in afully-automatic mode and in a semi-automatic mode. Other embodiments,however, may differ. For instance, in particular embodiments the firearmcan be a pistol.

Examples of methods include various methods of configuring a firearm(e.g., 10) to selectably eject shell casings through either side (e.g.,31 or 32) of the firearm. In this context, “selectably” means that anowner or operator of the firearm can select which side of the firearmthe shell casings are ejected from (e.g., by changing the orientation ofthe bolt). Some methods include at least one act of configuring thefirearm so that a bolt (e.g., 70) of the firearm can be installed in thefirearm in either of two different orientations, for example. In anumber of embodiments, when the bolt is installed in a first orientation(e.g., shown in FIG. 7), shell casings are ejected though a rightejection port (e.g., 42), and when the bolt is installed in a secondorientation (e.g., shown in FIG. 8), shell casings are ejected though aleft ejection port (e.g., 41), for instance. Other methods includemethods of obtaining or providing a firearm that will selectably ejectshell casings through either side of the firearm. In a number ofembodiments, such a method includes an act of obtaining or providing thefirearm (e.g., 10) wherein a bolt (e.g., 70) of the firearm can beinstalled in the firearm in either of two different orientations. Invarious embodiments, when the bolt is installed in a first orientation,shell casings are ejected though a right ejection port, and when thebolt is installed in a second orientation, shell casings are ejectedthough a left ejection port.

Further examples of methods include various methods of cooling a firearm(e.g., 10). Some methods include at least an act of opening two covers(e.g., 21 and 22) on opposite sides (e.g., 31 and 32) of the firearm(e.g., 10) when the firearm is discharged to provide cross ventilationthrough the firearm when the two covers are open. Further, in someembodiments, a method includes opening two ejection port covers (e.g.,21 and 22), specifically, on opposite sides of the firearm when thefirearm is discharged to provide cross ventilation through the firearmejection ports (e.g., specifically) when the two ejection port coversare open. For example, some embodiments include a first act of opening aleft cover (e.g., ejection port cover 21) and a second act of opening aright cover (e.g., 22). In different embodiments, the first act and thesecond act can be performed in either order or at the same time, asexamples.

Still other methods include methods of obtaining or providing a bolt(e.g., 70) for a firearm (e.g., 10) that will selectably eject shellcasings through either side of the firearm (e.g.,, using the same boltand without introducing or changing out any other parts of the firearm).Such methods can include, for example, obtaining or providing the boltof the firearm that can be installed in the firearm in either of twodifferent orientations such that when the bolt is installed in a firstorientation, shell casings are ejected though a right ejection port, andwhen the bolt is installed in a second orientation, shell casings areejected though a left ejection port. In various embodiments, particularmethods can include acts of obtaining or providing, as examples, otherfeatures, components, or aspects described herein. All possiblecombinations are contemplated. Further, methods described herein containvarious acts. The order in which these acts are described is an exampleof the order in which these acts can be performed, but in otherembodiments, unless stated otherwise herein, the acts may be performedin a different order. In some embodiments, acts may overlap or beperformed at the same time, as another example.

Still other specific embodiments include various bolts (e.g., 70) for afirearm (e.g., 10), the firearm having a left ejection port (e.g., 41)and a right ejection port (e.g., 42). In a number of embodiments, thebolt has a first side (e.g., 71) and a second side (e.g., 82) and isconfigured so that the bolt can be installed in the firearm (i.e.,operationally) with the first side up (e.g., as shown in FIG. 7) and thebolt can be installed in the firearm with the second side up (e.g., asshown in FIG. 8). In a number of embodiments, for example, when the boltis installed in the firearm with the first side up, shell casings areejected though the right ejection port (e.g., 42), and when the bolt isinstalled in the firearm with the second side up, shell casings areejected though the left ejection port (e.g., 41). Further, in someembodiments, a bolt for a firearm includes a first set of ejectionfeatures on a first side of the bolt and a second set of ejectionfeatures on a second side of the bolt, and the second set of ejectionfeatures is a mirror opposite of the first set of ejection features.Still further, various embodiments of bolts include other featuresdescribed herein. All possible combinations are contemplated.

Even further, various embodiments include providing a mechanism thatautomatically opens two ejection port covers (e.g., 21 and 22) onopposite sides (e.g., 31 and 32) of a firearm (e.g., 10), for example,when a bolt (e.g., 70) or carrier of the firearm moves, for instance, toprovide cross ventilation through the firearm ejection ports (e.g., 41and 42) when the two ejection port covers are open. Further still, someembodiments include obtaining or providing at least two protrusions(e.g., 91 and 92) on the bolt (e.g., 70) of the firearm (e.g., 10), forexample, that automatically open two ejection port covers (e.g., 21 and22) on opposite sides of the firearm when the bolt or carrier of thefirearm moves, for instance, to provide cross ventilation through thefirearm ejection ports (e.g., 41 and 42) when the two ejection portcovers are open.

Further, various embodiments of the subject matter described hereininclude various combinations of the acts, structure, components, andfeatures described herein, shown in the drawings, described in documentsthat are incorporated by reference herein, or that are known in the art.Moreover, certain procedures can include acts such as manufacturing,obtaining, or providing components that perform functions describedherein or in the documents that are incorporated by reference. Thesubject matter described herein also includes various means foraccomplishing the various functions or acts described herein, in thedocuments that are incorporated by reference, or that are apparent fromthe structure and acts described. Essentially, wherever a function isdescribed herein, and at least one example of structure is described,illustrated, or both, that performs that function, a means foraccomplishing that function is also contemplated.

Further, as used herein, the word “or”, except where indicatedotherwise, does not imply that the alternatives listed are mutuallyexclusive. Even further, where alternatives are listed herein, it shouldbe understood that in some embodiments, fewer alternatives may beavailable, or in particular embodiments, just one alternative may beavailable, as examples.

What is claimed is:
 1. A firearm comprising: a frame defining a boltpassage; a bolt operable to reciprocate within the bolt passage; and thebolt being rotationally symmetrical such that rotating it one half turnpresents the same form as without rotation.
 2. The firearm of claim 1further comprising the bolt having a bolt face having a downwardlydepending cartridge stripping surface, and a corresponding upwardlydepending cartridge stripping surface, wherein the cartridge strippingsurfaces are a pair of protrusions integral with, and radially spacedaround, the bolt face, each having a flat front face that engages a rimof a top cartridge to be stripped from a magazine.
 3. The firearm ofclaim 1 further comprising the bolt defining a central axis, and havingan extractor positioned in lateral alignment with the axis.
 4. Thefirearm of claim 4 wherein the downwardly depending cartridge strippingsurface and the corresponding upwardly depending cartridge strippingsurface are rotationally symmetrical with respect to one another.